Spectral distributions of photo-electrochemical reactions over metal phthalocyanine electrodes

Abstract

The spectral distributions of photo-electrochemical currents over cobalt, nickel and copper phthalocynanines were measured in the region 340 to 800 nm. Two distinctive spectra were obtained for each metal phthalocyanine, depending upon the type of the reaction; as an electron was donated from or accepted by the phthalocyanines. In the former case the peak maximum was observed at the shoulder of the Q band in the absorption spectra and in the latter case it was observed at the peak of the Q band. The difference in the photoaction was assumed to be due to the difference in the efficiency of conversion from the excited states to the charge carriers. This assumption was also supported by the fact that the photo-action spectrum for the oxidation was altered by the phase transition from α to β-phase in which the structure of the Q band changed.